Compounds disclosed in Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4 have been known as N-acyl cyclic amine derivatives having a psychotropic activity. However, these compounds have different chemical structures from the derivatives of the present invention.
Schizophrenia is a mental disorder with positive symptoms (e.g., hallucination, delusion), negative symptoms (e.g., apathy, social withdrawal), and cognitive dysfunction (e.g., disorders of working memory, attentional function and vigilance, verbal memory, visual learning and memory, movement velocity, abilities for executive function and business solution, sociocoginitive abilities, etc.) as a prominent symptom.
First-generation therapeutic agents for schizophrenia such as haloperidol show high therapeutic activities against positive symptoms, while they have not much effect on negative symptoms and cognitive dysfunction. Further, it has been known that said agents often cause side effects including extrapyramidal symptoms, hyperprolactinemia and oversedation. On the other hand, second-generation therapeutic agents for schizophrenia (e.g., olanzapine, risperidone), which have a current central role in drug therapy, improve positive symptoms as well as have effect on negative symptoms, and it has been said that said agents have low risks for onset of extrapyramidal side effects. However, it has not been said that even second-generation therapeutic agents for schizophrenia have enough therapeutic effects on negative symptoms and cognitive dysfunction. Moreover, new side effects including weight gain, sugar metabolic abnormality have become a problem in second-generation therapeutic agents for schizophrenia [Nonpatent Documents 1 to 2].
As such, compounds which show high efficacies in negative symptoms and cognitive dysfunction on which conventional therapeutic agents for schizophrenia have not had enough therapeutic effects, and those which reduce the risks for side effects in conventional therapeutic agents for schizophrenia are expected to be an agent which meets unmet needs in such fields. Further, compounds having high effects on improvement in cognition function are also effective in treatment of central neurological diseases associated with similar cognitive dysfunction including Alzheimer's disease, Parkinson disease, Huntington disease as well as cognitive dysfunction in schizophrenia.